Arrange the following elements in order from greatest to least tendency to accept an electron (i.e., from highest to lowest electron affinity): Cl, Na, S, P.

• A. P > S > Na > Cl
• B. S > P > Cl > Na
• C. Cl > S > P > Na
• D. Na > Cl > S > P

Answer: (C)

Verified step by step guidance

1. Understand that electron affinity refers to the tendency of an atom to accept an electron, generally increasing across a period from left to right and decreasing down a group in the periodic table.
2. Identify the positions of the elements Cl, Na, S, and P on the periodic table: Na is in Group 1 (alkali metals), P and S are in Period 3, Groups 15 and 16 respectively, and Cl is in Period 3, Group 17 (halogens).
3. Recall that halogens (like Cl) have the highest electron affinities in their period because they are one electron short of a full octet, making them very eager to gain an electron.
4. Compare the electron affinities of S and P, noting that S (Group 16) generally has a higher electron affinity than P (Group 15) due to its closer proximity to a filled p subshell.
5. Recognize that Na, being an alkali metal with a single valence electron, has the lowest electron affinity among the given elements because it tends to lose electrons rather than gain them.